a) Field of the Invention
The present invention relates to a (acoustically non-invasive) diagnostic system for coronary artery disease and others with a complex-multiple sensor system, which is usable in a bedside, and a diagnostic method for coronary artery desease and others using the above diagnostic system, more particularly, a diagnostic system for coronary artery disease and others having a set of detectors which detects very minute vascular murmur such as coronary artery stenotic, diastolic and other murmur, and a diagnostic method for coronary artery desease and others using the diagnostic system.
b) Description of Prior Arts
It is regulated in the Japanese Industrial Standard that a phonocardiograph can detect a heart sound signal of the frequency between 20 to 600 Hz, and the heart sound signal is that vibration signal deriving from heart and blood vessel is transmitted to body surface, which contains cardiac murmur.
The phonocardiograph comprises a heart sound microphone, a eqalizer (in the case of using a direct conductive microphone like an accelerometer microphone or a velocity microphone), a heart sound recorder, an electrocardiograph and a power supply, and it records the heart sound signal and the electrocardiographic signal simultaneously.
There are an aerial conductive microphone and the direct conductive microphone containing the accelerometer microphone or the velocity microphone and others as the heart sound microphone, and the phonocardiograph having a vibration sensor(detective sensor) like the above-mentioned heart sound microphone, an amplifier, a wave filter and an indicator, is produced in accordance with the Japanese Industrial Standard. The measurement of the phonocardiograph in accordance with the Japanese Industrial Standard is for detecting actuation abnormality of a valve and existence of an intracardiac shunt. However, in regard to very minute signal deriving from coronary artery stenosis during diastole and having wide frequency band between 200 to 1200 Hz, it is impossible to match the acoustic impedance between the heart sound microphone and the body surface if the weight of the microphone is not 5 g and less and ideally 1 g. Therefore, it is impossible for the phonocardiograph in accordance with the Japanese Industrial Standard to detect the very minute acoustic vibration signal between 200 to 1200 Hz.
As above-mentioned,
1, In the conventional practice, the very minute vibration signal of which frequency band between 200 to 1200 Hz is out of the Japanese Industrial Standard, and the above signal is out of the frequency of the measured object of the phonocardiograph. PA0 2, As the vibration intensity of such very minute vibration signal is very weak, it needs to be amplified over 100 dB in order to make the above signal to be the measured object. In the case of using an acoustic vibration sensor like an microphone and an accelerometer as the detective sensor of the phonocardiograph for the above amplification, the matching of the acoustic impedance between the sensor and the body surface cannot be taken since the weight of the sensor becomes over 200 g. PA0 3, Though the sensor technology by the displacement gage principle is in the conventional practice, the satisfied detection cannot be carried out because the sensitivity is insufficient and the vibration signal of the object is buried in the noise. PA0 4, A time resolution is also insufficient in the conventional practice using the vibration sensor such as a microphone by vibrating plate resonance or an accelerometer by charge generation based on enclosure resonance. PA0 5, Though the phonocardiograph using the laser interferometer had not been devised, the object of this is the heart sound. There is no system which can perceive and detect the very minute displacement vibration signal like coronary artery stenotic, diastolic and other murmur.